Mosquitoes actually are not replaceable in any ecosystem that naturally has them and that includes replacing them with any of the non biting species because these are the traits that make them so core to food webs:

• Tiny
• Can use every single pool of moisture to raise generations no matter how dirty and stagnant and low in oxygen
• Can fly
• Males get by on just sugars
• Females take protein from larger animals to manufacture thousands more eggs

All these things combined allow thst ecosystem to make huge volumes of insects from conditions barren to most other macroscopic life. You might think there are other insects that seem to make huge massive swarms out of nothing but there’s really nothing that hits all the same qualities *except other insects that also suck blood.*

It’s the precise combo of being able to “prey” on things millions of times larger and breed in nothing but a few drops of filthy rainwater or the moisture in a rotten log. That’s the most efficient combination for anything that size to multiply that rapidly where nothing else can even survive, except of course the things that can move in because they eat them :)